/*
 * ***** BEGIN LICENSE BLOCK *****
 * Copyright (c) 2011-2012 VMware, Inc.
 *
 * For the license see COPYING.
 * ***** END LICENSE BLOCK *****
 */

utils.attachMessage = function(listener) {
    utils.attachEvent('message', listener);
};

utils.attachEvent = function(event, listener) {
    if (typeof _window.addEventListener !== 'undefined') {
        _window.addEventListener(event, listener, false);
    } else {
        // IE quirks.
        // According to: http://stevesouders.com/misc/test-postmessage.php
        // the message gets delivered only to 'document', not 'window'.
        _document.attachEvent("on" + event, listener);
        // I get 'window' for ie8.
        _window.attachEvent("on" + event, listener);
    }
};

utils.detachMessage = function(listener) {
    utils.detachEvent('message', listener);
};

utils.detachEvent = function(event, listener) {
    if (typeof _window.addEventListener !== 'undefined') {
        _window.removeEventListener(event, listener, false);
    } else {
        _document.detachEvent("on" + event, listener);
        _window.detachEvent("on" + event, listener);
    }
};


var on_unload = {};
// Things registered after beforeunload are to be called immediately.
var after_unload = false;

var trigger_unload_callbacks = function() {
    for(var ref in on_unload) {
        on_unload[ref]();
        delete on_unload[ref];
    };
};

var unload_triggered = function() {
    if(after_unload) return;
    after_unload = true;
    trigger_unload_callbacks();
};

// 'unload' alone is not reliable in opera within an iframe, but we
// can't use `beforeunload` as IE fires it on javascript: links.
utils.attachEvent('unload', unload_triggered);

utils.unload_add = function(listener) {
    var ref = utils.random_string(8);
    on_unload[ref] = listener;
    if (after_unload) {
        utils.delay(trigger_unload_callbacks);
    }
    return ref;
};

utils.unload_del = function(ref) {
    if (ref in on_unload)
        delete on_unload[ref];
};

utils.createIframe = function (iframe_url, error_callback) {
    var iframe = _document.createElement('iframe');
    var tref, unload_ref;
    var unattach = function() {
        clearTimeout(tref);
        // Explorer had problems with that.
        try {iframe.onload = null;} catch (x) {}
        iframe.onerror = null;
    };
    var cleanup = function() {
        if (iframe) {
            unattach();
            // This timeout makes chrome fire onbeforeunload event
            // within iframe. Without the timeout it goes straight to
            // onunload.
            setTimeout(function() {
                if(iframe) {
                    iframe.parentNode.removeChild(iframe);
                }
                iframe = null;
            }, 0);
            utils.unload_del(unload_ref);
        }
    };
    var onerror = function(r) {
        if (iframe) {
            cleanup();
            error_callback(r);
        }
    };
    var post = function(msg, origin) {
        try {
            // When the iframe is not loaded, IE raises an exception
            // on 'contentWindow'.
            if (iframe && iframe.contentWindow) {
                iframe.contentWindow.postMessage(msg, origin);
            }
        } catch (x) {};
    };

    iframe.src = iframe_url;
    iframe.style.display = 'none';
    iframe.style.position = 'absolute';
    iframe.onerror = function(){onerror('onerror');};
    iframe.onload = function() {
        // `onload` is triggered before scripts on the iframe are
        // executed. Give it few seconds to actually load stuff.
        clearTimeout(tref);
        tref = setTimeout(function(){onerror('onload timeout');}, 2000);
    };
    _document.body.appendChild(iframe);
    tref = setTimeout(function(){onerror('timeout');}, 15000);
    unload_ref = utils.unload_add(cleanup);
    return {
        post: post,
        cleanup: cleanup,
        loaded: unattach
    };
};

utils.createHtmlfile = function (iframe_url, error_callback) {
    var doc = new ActiveXObject('htmlfile');
    var tref, unload_ref;
    var iframe;
    var unattach = function() {
        clearTimeout(tref);
    };
    var cleanup = function() {
        if (doc) {
            unattach();
            utils.unload_del(unload_ref);
            iframe.parentNode.removeChild(iframe);
            iframe = doc = null;
            CollectGarbage();
        }
    };
    var onerror = function(r)  {
        if (doc) {
            cleanup();
            error_callback(r);
        }
    };
    var post = function(msg, origin) {
        try {
            // When the iframe is not loaded, IE raises an exception
            // on 'contentWindow'.
            if (iframe && iframe.contentWindow) {
                iframe.contentWindow.postMessage(msg, origin);
            }
        } catch (x) {};
    };

    doc.open();
    doc.write('<html><s' + 'cript>' +
              'document.domain="' + document.domain + '";' +
              '</s' + 'cript></html>');
    doc.close();
    doc.parentWindow[WPrefix] = _window[WPrefix];
    var c = doc.createElement('div');
    doc.body.appendChild(c);
    iframe = doc.createElement('iframe');
    c.appendChild(iframe);
    iframe.src = iframe_url;
    tref = setTimeout(function(){onerror('timeout');}, 15000);
    unload_ref = utils.unload_add(cleanup);
    return {
        post: post,
        cleanup: cleanup,
        loaded: unattach
    };
};
